Add complex randn #21973
Add complex randn #21973
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ararslan
added
domain:complex
base/random.jl
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| @@ -1194,6 +1196,9 @@ The `Base` module currently provides an implementation for the types | |||
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| end | |||
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| Base.@irrational SQRT_HALF 0.7071067811865475244008 sqrt(big(0.5)) | |||
| randn{T}(rng::AbstractRNG, ::Type{Complex{T}}) = Complex{T}(SQRT_HALF * randn(rng, T), SQRT_HALF*randn(rng, T)) | |||
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For new code, maybe use the where syntax. Also, don't you want to restrict T<:AbstractFloat?
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Ah right I forgot about the new where syntax. Good call about restriction at the call site. I wasn't sure if should just let it blow up at the call the randn(rng, T), but it does makes the error message a little more cryptic doesn't it.
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I think it would make an InexactError when calling the complex constructor on real (because of the multiplication by SQRT_HALF) values, e.g. with T==Int. Also, this distribution will make sense only when randn(T) produces a number in [0,1), i.e. T<:AbstractFloat.
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I'm not sure I understand what you mean by this. Can you explain another way?
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LGTM. |
base/random.jl
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| # complex randn | ||
| Base.@irrational SQRT_HALF 0.7071067811865475244008 sqrt(big(0.5)) | ||
| randn(rng::AbstractRNG, ::Type{Complex{T}}) where {T <: Floats} = Complex{T}(SQRT_HALF * randn(rng, T), SQRT_HALF*randn(rng, T)) |
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I'm not sure if we want T<:Floats or T<:AbstractFloat. E.g. if someone defines randn(::CustomRNG, ::BigFloat), she won't benefit from your complex randn definition...
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Done, also added a statement to the NEWS
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cc @stevengj , @andreasnoack , @simonbyrne |
base/random.jl
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| end | ||
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| # complex randn | ||
| Base.@irrational SQRT_HALF 0.7071067811865475244008 sqrt(big(0.5)) | ||
| randn(rng::AbstractRNG, ::Type{Complex{T}}) where {T <: AbstractFloat} = Complex{T}(SQRT_HALF * randn(rng, T), SQRT_HALF*randn(rng, T)) |
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inconsistent spacing after SQRT_HALF
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Yup. This line is a little long as well. I'll break it at the =.
base/random.jl
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| @@ -1282,8 +1284,13 @@ let Floats = Union{Float16,Float32,Float64} | |||
| $randfun( dims::Integer... ) = $randfun(GLOBAL_RNG, Float64, dims...) | |||
| end | |||
| end | |||
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oops, not sure how that got there..
Implements sampling from a complex normal distribution by adding a method to
randn.Extends work done in #17725 by applying some suggestions mentioned there. Fixes #21859.